<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
</head>
<body>
<canvas id="myCanvas" width="500" height="500" style="border:1px solid #000000;">
</canvas>
</body>
</html>
<script type="text/javascript">
	var c=document.getElementById("myCanvas");
    var ctx=c.getContext("2d");   
    ctx.shadowBlur=30;    
    ctx.shadowOffsetX=20;    
    ctx.shadowColor="black";    
    ctx.fillStyle="#0000FF";    
    ctx.fillRect(20,20,100,80);
</script>